1. Field of the Invention
The present invention relates to a system for managing a consumption quantity of consumables used for printing by a printer, a terminal, a printer, a program and a method, and in particular to a device management system, a printer management system, a printer management terminal, a network printer, a program for a terminal and a program for a printer, and a device management method, suitable for accurately calculating an average consumption quantity of toner and the like per print sheet and thereby accurately calculating a printing cost depending on use environments.
2. Description of the Prior Art
When installing a printer in an office, it is desired to install a printer with running cost as low as possible from a viewpoint of cost reduction. As an example of a running cost, a cost equivalent to an average consumption quantity of toner/ink per print sheet (hereinafter simply referred to as a printing cost) is known as an index, and it is the only way to obtain the index to adopt a value announced by a printer manufacturer at present. However, the printing cost announced by a printer manufacturer is a value obtained when a printing sample appointed by the printer manufacturer is printed. Therefore, it is not necessarily applicable to an actual situation because the printing cost varies according to printed contents.
Accordingly, a technique for managing a printer according to use environments can be used. Prior-art techniques for managing a printer and related techniques include, for example, an image forming device disclosed in Patent Document 1 (hereinafter referred to as a first prior-art example), a print information processing method for a page printer, disclosed in Patent Document 2 (hereinafter referred to as a second prior-art example), a printing system disclosed in Patent Document 3 (hereinafter referred to as a third prior-art example), and a consumables management system disclosed in Patent Document 4 (hereinafter referred to as a fourth prior-art example).
In the first prior-art example, it is determined whether or not there is developer with an antenna electrode plate by utilizing change in electrostatic capacity based on the quantity of toner between a development sleeve and the antenna electrode; the number of recording material sheets received and outputted within a predetermined time is detected; an equation of W=f(V), which indicates relation between a toner capacity W and a remaining toner detection output voltage V, is stored in advance; the number of days for which the remaining toner can be used is estimated based on the initial toner capacity, the toner capacity after N sheets have been received and outputted, the quantity of toner from which it is determined that there is no toner, and an average toner consumption quantity per sheet when N sheets are received and outputted with the remaining toner output voltage. Furthermore, the number of days, for which the remaining sheets can be used, is estimated based on the number of the remaining sheets detected by a remaining sheet quantity detecting portion and the above-mentioned number of received and outputted sheets. Here, an average toner consumption quantity per sheet when received N sheets are outputted is calculated by (Wi−ω))/N=(Wi−f(υ))/N based on ω=f(υ), where the initial toner capacity is indicated by Wi, the toner capacity after received N sheets are outputted is indicated by ω, and the remaining toner detection output voltage is indicated by υ. This enables a user to be accurately informed of the time for replenishing toner and sheets.
In the second prior-art example, there are executed steps of: calculating the black pixel ratio for each page of print data in a page memory to update the number of printed sheets and the printing ratio, and accumulatingly storing them in a statistic memory; determining the current time, updating the average number of printed sheets and printing ratio per day based on the number of printed sheets and printing ratio for the day stored in the statistic memory to store them in the statistical memory at the end of the day, and updating the average number of printed sheets and printing ratio per month based on the average number of printed sheets and printing ratio per day stored in the statistical memory to store them in the statistical memory at the end of the month; and displaying the average number of printed sheets and printing ratio per month, per day and the number of printed sheets and printing ratio for the day. This makes it possible to accumulatingly update the number of printed sheets and the black pixel ratio of the printed sheets after exchange of a unit to use them as statistic data, and thereby the time for exchanging the unit can be accurately predicted.
The third prior-art example, there are provided a printer including a printer control portion, consumables, a storage portion and a network communication portion and accumulating printing history information in the storage portion for each data printing, and a host computer which is connected to the printer and provided with a network communication portion, a date management portion for dates to exchange consumables and the like, a portion for reading the printing history information, a portion for predicting the time for exchanging consumables based on the printing history information read from the printer, and a display portion for displaying the predicted result for each of the consumables. The interval for monitoring printing information accumulated in the printer can be changed from the host computer. Thus, it is possible to efficiently and accurately predict life of parts to be exchanged and consumables and notify it to a user even in the case of utilization on a network.
In the fourth prior-art example, when a toner low signal is sent from a user's equipment to a service center, the service center predicts the time when the toner is run down, based on the type of the cartridge and the time when the toner low signal was generated. The result of the prediction is notified to the user, and cartridge delivery/recovery is performed by a delivery company at the date and time agreed with by the user. Thus, as for toner provided in a cartridge, it is possible to accurately predict the time when the toner is run down and recommend exchange thereof.
(Patent Document 1)
Published Unexamined Patent Application No. 8-234555
(Patent Document 2)
Published Unexamined Patent Application No. 9-22227
(Patent Document 3)
Published Unexamined Patent Application No. 2000-71581
(Patent Document 4)
Published Unexamined Patent Application No. 2001-228761
As described above, in the first prior-art example, an average toner consumption quantity per sheet when received N sheets are outputted is calculated based on an initial toner capacity Wi, a toner capacity ω after received N sheets are outputted and a remaining toner detection output voltage υ. However, a printer performs warm-up operation, cleaning operation and the like when it is powered on and activated, and toner or ink (hereinafter referred to as toner and the like) is consumed during the operation although only slightly. Therefore, if activation is repeated, the average toner consumption quantity per sheet when received N sheets are outputted cannot be accurately calculated from the above arithmetic expression.
In the second prior-art example, only an average number of printed sheets and printing ratio per month and per day, and the number of printed sheet and printing ratio for the day are calculated and displayed, and the average toner consumption quantity per print sheet cannot be accurately calculated.
In the third prior-art example, the time for exchanging toner and the like of a printer is predicted by comparing the number of actually printed sheets and a predetermined value for a consumption degree of toner and the like of a printer. In the fourth prior-art example, remaining quantity alert information is obtained, which indicates that the remaining quantity of toner and the like has reached a predetermined amount, and the date when the toner and the like is run down is predicted based on the obtained remaining quantity alert information. In these cases, however, the average consumption quantity of toner and the like per print sheet cannot be accurately calculated because consumption of toner and the like during activation is not taken into consideration.
Accordingly, the first to fourth prior-art examples have a problem that it is difficult to accurately calculate a printing cost depending on use environments.
Furthermore, in printers used at present, the value of the remaining quantity of toner and the like, which can be obtained from a printer, is not necessarily accurate. For example, the detection accuracy is in increments of 2%. Therefore, it is not possible to accurately calculate an average consumption quantity of toner and the like per print sheet. Thus, there is a problem that it is difficult to accurately calculate a printing cost depending on use environments.
This problem is not limited to a printer but can be assumed for any device the operation of which consumes consumables.
Accordingly, the present invention has been made in consideration of the unsolved problem of the prior-art techniques. The object of the invention is to provide a device management system, a printer management system, a printer management terminal, a network printer, a program for a terminal and a program for a printer, and a device management method, suitable for accurately calculating an average consumption quantity of toner and the like per print sheet and thereby accurately calculating a printing cost depending on use environments.